Prior Art
Typical hydroelectric power plant installations utilize Francis turbines (FIG. 1) that separate the turbine 31 from the exciter 32 and rotor 33 carrying the generator's magnets with an extended shaft 34. This introduces additional weight that reduces efficiency and requires significantly more space in the power house. The rotating weight of these turbine/generators is, on average, eight hundred tons.
Low head dams and reservoirs, on the other hand, incorporate Bulb turbine/generators (FIG. 2) that also separate the exciter 35, rotor 36, and gearbox 37 from the turbine blades 38 with an extended shaft 39, again introducing additional weight and complexity. This design limits the size of the rotor and thus the amount of electricity generated.
The referenced HOLLOW TURBINE, and similar designs, allow passing fluids to come into direct contact with the spinning turbine's inner cylinder wall 40. This adds unnecessary weight and drag on the rotating turbine 41. FIG. 3 depicts a tidal installation including: directional funnels 42, rotational energy connecting elements 43, two rotors 44 and two sets of stators 45. The vacant axis of rotation 46 allows fish and debris to safely pass through the turbine 41.
Other all-in-one hydroelectric turbine/generators such as Anderson et al. (U.S. Pat. No. 4,720,640), not shown, are built on a single shaft located at the rotor/turbine's axis of rotation. This design introduces complexity that results in high maintenance costs, as well as exposing critical apparatus to damage from passing debris. Fish mortality is high when passing fish get caught in between the spinning turbine blades and the stator's support structure.